Transition probabilities of Er3+ ions in alumino-silicate glasses

The spectroscopic properties of Er-doped Ca3Al2Si3O12 and Mg3Al2Si3O12 glasses produced by the Laser Floating Zone technique are presented in this work. By measuring the absorption spectra and refractive index dispersion of the materials, JO parameters of the Er3+ ions have been obtained in both doped materials, where very good accordance between the experimental and theoretical electric dipole oscillator strengths is found. Using calculated electric and magnetic dipole strengths, the branching ratios of the different optical transition of Er3+ in Ca and Mg glasses have been obtained, where the radiative lifetime of each level has been also calculated. The experimental lifetimes of the 4S3/2, 4I11/2 and 4I13/2 manifolds have been measured under pulse excitation. These values have been related with the radiative lifetime calculated by the JO analysis, allowing to determine the non-radiative probabilities of the levels. In addition, a gap law has been established for both Ca and Mg alumino-silicate glasses. Finally, the covalency of the Er-O bond was studied in terms of the spectroscopic features of these glasses.